This invention relates to a process for coating the adhesive surfaces of structural or support elements and, in particular, of fastening elements.
This invention focuses specifically on the application of highly reactive hot melt adhesives which, on exposure to temperatures up to 50.degree. C., are wear-resistant and nonsticking and which can be reactivated on exposure to heat or some other kind of energy so as to produce a permanent adhesive joint. The adhesive coating applied to the surface must be totally nonsticky and adhesion-resistant until the fastening element is used, and the adhesive force inherent in the adhesive should be triggered only after the adhesive has been reactivated at the site of application.
It is known from German Patent No. DE 44 02 550 A1 that hot melt adhesive can be applied to the adhesive surface of a plate by lowering the fastening element with the adhesive surface face down into a hot melt adhesive bath and by lifting it again as soon as the entire adhesive surface has been wetted with a sufficient quantity of adhesive. The adhesive layer adhering to the lower surface has to be dried before the fastening elements can be packaged and transported to the application site to prevent the fastening element from sticking together.
This procedure, however, is relatively cumbersome and time-consuming since the fastening elements must be separately grasped, after which they are immersed into the hot melt adhesive bath with the adhesive surface facing down, which is followed by a drying step.